833,552. Moulding foamed sealing strips. STERLING ALDERFER CO. Sept. 23, 1957, No. 29866/57. Class 87(2). [Also in Group X] Sealing strips are formed by depositing a chargeof unexpanded material which will react to form a foam on a moving web of flexible material, joining the edges of the web to form a jacket and allowing the reaction to run in the jacket. As shown in Fig. 1 apparatus for the manufacture of the sealing strip includes an air tight mixing chamber 19, including a mixing screw 20 rotated at a speed depending on the mixture, to which polyester, polyether or like compounds, water and the catalyst are pumped from tank 1 and a suitable isocyanate or polyisocyanate is pumped from tank 2. The mixture is then fed through a flexible tube 25 on to the lowermost portion of a web of polyethylene film which forms the sealing strip jacket. The web is drawn. from a drum 33 by the action of the sealer 60 (see below) and is folded by passing over a triangular plate having two upstanding side flanges so that the sides of the web are drawn together. The upper parts of the web are sealed together to form a flap by a pair of endless stainless steel resistance heated belts or tapes 68, Fig. 3. The web then passes between two pillars 81 one of which is adjustable' so that the reactant mixture is compressed to exclude air. The sealed web is then fed onto a chain 92 which carries groups of pins 94 which pierce the flap and suspend the strip until the reaction is complete. The sealing pattern is such that rectangles 140 and 142, Fig. 20, of the lapping edges are sealed together thus leaving passages 141 extending transversely of the core along which the foam expands. Alternatively, Fig. 23, the lapping edges are sealed together at small rectangles 144, 145 between which the foam expands. In a second embodiment the web is a vinyl film and is coated before folding with an adhesive, or an adhesive coated vinyl tape is sealed to the lapping portions during the sealing operation which in this case would be by induction heating. The lapping edges may also be stitched together.
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